"We are going to use this technology in problem areas, where taggers are most active," the spokesman told AFP.

The drones can fly at altitudes of up to 150 metres and travel at up to 54 kilometres per hour.

Deutsche Bahn said it suffered property damage worth 7.6 million euros ($10 million) from people spray-painting its carriages last year.

The rail operator said it would only use the drones over its own depots, not in public areas, in line with German anti-surveillance laws.

Internet giant Google ran into problems in Germany when it filmed streets for its global Street View project, with thousands of residents complaining and Google being forced to blur many of the images.